Coberturas vegetais e modos de inoculação com Azospirillum brasilense em milho sobre três sistemas de preparo de solo
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Data
2018-07-02
Autores
Corsini, Daiene Camila Dias Chaves
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Universidade Estadual Paulista (Unesp)
Resumo
Devido ao crescimento e a importância da utilização do milho segunda safra, pacotes tecnológicos que favoreçam o uso dessa nova época de cultivo para o milho são de extrema importância para a consolidação dessa safra. O manejo adequado do solo, a utilização de coberturas vegetais e considerando também os dados pouco consistentes na utilização da inoculação com bactérias promotoras de crescimento na cultura do milho, são práticas fundamentais para a busca de uma produção econômica e ambientalmente viável. Diante do exposto o objetivo desse trabalho foi o de avaliar o efeito das coberturas vegetais e dos modos de inoculação com Azospirillum brasilense nos diferentes sistemas de preparo do solo, no desenvolvimento e produtividade do milho segunda safra. O experimento foi desenvolvido nos anos agrícolas de 2013/14 e 2014/15 em área experimental da Fazenda de Ensino e Pesquisa pertencente à Faculdade de Engenharia de Ilha Solteira – UNESP, localizada no município de Selvíria – MS. O solo do local é do tipo LATOSSOLO VERMELHO-ESCURO Epi-eutrófico álico, textura argilosa, originalmente sob vegetação de cerrado. A precipitação média anual é de 1.313 mm e a temperatura média anual de 25°C. A área teve como cultura anterior a soja, e foi constituído por três subprojetos envolvendo coberturas vegetais (Crotalária spectabilis, Urochloa ruziziensis e C. spectabilis + U. ruziziensis), modos de inoculação com A. brasilense (testemunha - sem inoculação de A. brasilense, inoculação de A. brasilense nas sementes do milho, inoculação de A. brasilense na semente do milho e via foliar - estádio V4 e inoculação de A. brasilense via foliar - estádio V4) em três sistemas de preparo de solo (plantio direto, cultivo mínimo e cultivo convencional). Os delineamentos experimentais foram de blocos casualizados em esquema de parcelas subdivididas em cada tipo de preparo do solo (subprojetos), sendo constituídos por três coberturas vegetais e quatro modos de inoculação com quatro repetições. Observou-se que no subprojeto com coberturas vegetais e modos de inoculação em sistema plantio direto, as coberturas vegetais obtiveram biomassa adequada para a manutenção de palha nesse sistema; a C. spectabilis obteve os maiores teores de nitrogênio (N) nas plantas e N acumulado, proporcionando as plantas de milho cultivadas após essa cobertura, maior altura de inserção de espigas; as plantas de milho cultivadas após a U. ruziziensis apresentou um maior população de Azospirillum por grama de solo. No cultivo mínimo, as coberturas vegetais obtiveram biomassa adequada para a manutenção de palha; para o teor de N, a espécie C. spectabilis apresentou maiores médias proporcionando as plantas de milho maior a altura de inserção de espiga, maior massa de plantas e maior população Azospirillum por grama de solo; a inoculação com A. brasilense via foliar proporcionou as plantas de milho maior massa seca de parte aérea; o modo de inoculação com A. brasilense proporcionou aumento da produtividade de grãos de milho quando essa foi feita nas sementes e via foliar. No sistema de preparo de solo convencional, as coberturas vegetais obtiveram biomassa adequada para a manutenção de palha, a massa seca de plantas de U. ruziziensis teve o maior valor médio e o maior acúmulo de N; a altura de plantas e altura de inserção de espigas foi maior quando houve a inoculação nas sementes de milho e via foliar com A. brasilense.
Due to the growth and importance of the use of second crop maize, technological packages that enhance the use of this new maize season are extremely important for this crop consolidation. Adequate soil management, cover crops and also the inconsistent data on the use of inoculation with growth promoting bacteria in maize, are fundamental practices for the search for an economically and environmentally viable production. This study animed to evaluate the effect of plant cover and inoculation methods with Azospirillum brasilense on different soil preparation systems, on the development and productivity of second crop maize. The experiment was developed in the agricultural years of 2013/14 and 2014/15 in an experimental area of the Education and Research Farm belonging to the Faculty of Engineering of Ilha Solteira - UNESP, located in the municipality of Selvíria -MS. The soil of the site is of the type RED-DARK LATOSOL Epi-eutrophic alic, clayey texture, originally under cerrado vegetation. The average precipitation cancels out is 1313 mm and the average annual temperature is 25 ° C. The area was previously cultivated with soybean, and was constituted by three subprojects involving plant cover crops (Crotalaria spectabilis, Urochloa ruziziensis and C. spectabilis + U. ruziziensis), inoculation methods with A. brasilense (control - without inoculation of A. brasilense , inoculation of A. brasilense on maize seeds, inoculation of A. brasilense on maize seed and foliar - V4 stage and inoculation of A. brasilense via foliar - V4 stage) in three soil tillage systems (no - tillage, no - tillage minimum and conventional cultivation). The experimental design was a randomized block design subdivided in each type of soil preparation (subprojects), consisting of three vegetation cover and four modes of inoculation with four replications. It was observed that in the subproject with vegetation cover and inoculation methods in no-tillage system, the vegetal cover obtained adequate biomass for the maintenance of straw in this system; C. spectabilis obtained the highest levels of nitrogen in the plants and N accumulated, providing the maize plants cultivated after this cover, greater height of spike insertion; maize plants grown after U. ruziziensis showed a larger population of Azospirillum per gram of soil. In the minimum cultivation, the vegetal coverings obtained adequate biomass for the maintenance of straw; for the N content, the species C. spectabilis showed higher mean values, giving the maize plants greater spike insertion height, larger plant mass and higher Azospirillum population per soil gram; the inoculation with A. brasilense via foliar provided the maize plants with the highest aerial part dry mass; the form of inoculation with A. brasilense provided an increase in the yield of maize grains when it was made in the seeds and foliar route. In the conventional tillage system, the plant cover obtained adequate biomass for the maintenance of straw, the dry mass of U. ruziziensis plants had the highest average value and the highest accumulation of N; plant height and spike insertion height were higher when inoculation was carried out on maize seeds and foliar route with A. brasilense.
Due to the growth and importance of the use of second crop maize, technological packages that enhance the use of this new maize season are extremely important for this crop consolidation. Adequate soil management, cover crops and also the inconsistent data on the use of inoculation with growth promoting bacteria in maize, are fundamental practices for the search for an economically and environmentally viable production. This study animed to evaluate the effect of plant cover and inoculation methods with Azospirillum brasilense on different soil preparation systems, on the development and productivity of second crop maize. The experiment was developed in the agricultural years of 2013/14 and 2014/15 in an experimental area of the Education and Research Farm belonging to the Faculty of Engineering of Ilha Solteira - UNESP, located in the municipality of Selvíria -MS. The soil of the site is of the type RED-DARK LATOSOL Epi-eutrophic alic, clayey texture, originally under cerrado vegetation. The average precipitation cancels out is 1313 mm and the average annual temperature is 25 ° C. The area was previously cultivated with soybean, and was constituted by three subprojects involving plant cover crops (Crotalaria spectabilis, Urochloa ruziziensis and C. spectabilis + U. ruziziensis), inoculation methods with A. brasilense (control - without inoculation of A. brasilense , inoculation of A. brasilense on maize seeds, inoculation of A. brasilense on maize seed and foliar - V4 stage and inoculation of A. brasilense via foliar - V4 stage) in three soil tillage systems (no - tillage, no - tillage minimum and conventional cultivation). The experimental design was a randomized block design subdivided in each type of soil preparation (subprojects), consisting of three vegetation cover and four modes of inoculation with four replications. It was observed that in the subproject with vegetation cover and inoculation methods in no-tillage system, the vegetal cover obtained adequate biomass for the maintenance of straw in this system; C. spectabilis obtained the highest levels of nitrogen in the plants and N accumulated, providing the maize plants cultivated after this cover, greater height of spike insertion; maize plants grown after U. ruziziensis showed a larger population of Azospirillum per gram of soil. In the minimum cultivation, the vegetal coverings obtained adequate biomass for the maintenance of straw; for the N content, the species C. spectabilis showed higher mean values, giving the maize plants greater spike insertion height, larger plant mass and higher Azospirillum population per soil gram; the inoculation with A. brasilense via foliar provided the maize plants with the highest aerial part dry mass; the form of inoculation with A. brasilense provided an increase in the yield of maize grains when it was made in the seeds and foliar route. In the conventional tillage system, the plant cover obtained adequate biomass for the maintenance of straw, the dry mass of U. ruziziensis plants had the highest average value and the highest accumulation of N; plant height and spike insertion height were higher when inoculation was carried out on maize seeds and foliar route with A. brasilense.
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Palavras-chave
Preparo do solo, Zea mays L., Bactérias promotoras de crescimento de plantas, Fixação biológica de nitrogênio, Fisiologia, Segunda safra, Urochloa ruziziensis, Crotalária spectabilis, Soil preparation, Plant growth promoting bacteria, Biological fixation of nitrogen, Physiology, Second harvest